US4017518A - Method of preparing 4,4-dimethyldioxane-1,3 - Google Patents
Method of preparing 4,4-dimethyldioxane-1,3 Download PDFInfo
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- US4017518A US4017518A US05/569,388 US56938875A US4017518A US 4017518 A US4017518 A US 4017518A US 56938875 A US56938875 A US 56938875A US 4017518 A US4017518 A US 4017518A
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- formaldehyde
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- dimethyldioxane
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- 238000000034 method Methods 0.000 title claims abstract description 29
- GDKSTFXHMBGCPG-UHFFFAOYSA-N 4,4-dimethyl-1,3-dioxane Chemical compound CC1(C)CCOCO1 GDKSTFXHMBGCPG-UHFFFAOYSA-N 0.000 title claims abstract description 21
- WSFSSNUMVMOOMR-UHFFFAOYSA-N Formaldehyde Chemical compound O=C WSFSSNUMVMOOMR-UHFFFAOYSA-N 0.000 claims abstract description 119
- 239000003054 catalyst Substances 0.000 claims abstract description 22
- 150000003839 salts Chemical class 0.000 claims abstract description 22
- 239000007795 chemical reaction product Substances 0.000 claims abstract description 21
- 239000008346 aqueous phase Substances 0.000 claims abstract description 19
- VQTUBCCKSQIDNK-UHFFFAOYSA-N Isobutene Chemical group CC(C)=C VQTUBCCKSQIDNK-UHFFFAOYSA-N 0.000 claims abstract description 18
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 17
- 239000012074 organic phase Substances 0.000 claims abstract description 14
- 239000012071 phase Substances 0.000 claims abstract description 9
- 239000007864 aqueous solution Substances 0.000 claims abstract description 6
- 239000012736 aqueous medium Substances 0.000 claims abstract description 4
- 239000002253 acid Substances 0.000 claims abstract description 3
- 150000007513 acids Chemical class 0.000 claims abstract description 3
- 229910052500 inorganic mineral Inorganic materials 0.000 claims abstract description 3
- 239000011707 mineral Substances 0.000 claims abstract description 3
- 238000005406 washing Methods 0.000 claims abstract description 3
- 238000006243 chemical reaction Methods 0.000 claims description 43
- WSFSSNUMVMOOMR-NJFSPNSNSA-N methanone Chemical compound O=[14CH2] WSFSSNUMVMOOMR-NJFSPNSNSA-N 0.000 claims description 9
- 239000003153 chemical reaction reagent Substances 0.000 claims description 7
- VBKNTGMWIPUCRF-UHFFFAOYSA-M potassium;fluoride;hydrofluoride Chemical compound F.[F-].[K+] VBKNTGMWIPUCRF-UHFFFAOYSA-M 0.000 claims description 4
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 claims description 3
- GRWVQDDAKZFPFI-UHFFFAOYSA-H chromium(III) sulfate Chemical compound [Cr+3].[Cr+3].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O GRWVQDDAKZFPFI-UHFFFAOYSA-H 0.000 claims description 3
- 238000004821 distillation Methods 0.000 claims description 3
- 229910021556 Chromium(III) chloride Inorganic materials 0.000 claims description 2
- OIDPCXKPHYRNKH-UHFFFAOYSA-J chrome alum Chemical compound [K]OS(=O)(=O)O[Cr]1OS(=O)(=O)O1 OIDPCXKPHYRNKH-UHFFFAOYSA-J 0.000 claims description 2
- 229960000359 chromic chloride Drugs 0.000 claims description 2
- QSWDMMVNRMROPK-UHFFFAOYSA-K chromium(3+) trichloride Chemical compound [Cl-].[Cl-].[Cl-].[Cr+3] QSWDMMVNRMROPK-UHFFFAOYSA-K 0.000 claims description 2
- BNGXYYYYKUGPPF-UHFFFAOYSA-M (3-methylphenyl)methyl-triphenylphosphanium;chloride Chemical compound [Cl-].CC1=CC=CC(C[P+](C=2C=CC=CC=2)(C=2C=CC=CC=2)C=2C=CC=CC=2)=C1 BNGXYYYYKUGPPF-UHFFFAOYSA-M 0.000 claims 1
- 230000015572 biosynthetic process Effects 0.000 abstract description 9
- 230000003993 interaction Effects 0.000 abstract description 6
- 238000000926 separation method Methods 0.000 abstract description 2
- 238000002955 isolation Methods 0.000 abstract 1
- 239000000203 mixture Substances 0.000 description 13
- 239000000047 product Substances 0.000 description 10
- 238000004064 recycling Methods 0.000 description 10
- 238000001704 evaporation Methods 0.000 description 9
- 230000008020 evaporation Effects 0.000 description 8
- 238000002360 preparation method Methods 0.000 description 8
- 238000003786 synthesis reaction Methods 0.000 description 8
- 229910001220 stainless steel Inorganic materials 0.000 description 7
- 239000010935 stainless steel Substances 0.000 description 7
- 238000009835 boiling Methods 0.000 description 5
- 238000001816 cooling Methods 0.000 description 5
- 238000002474 experimental method Methods 0.000 description 5
- 239000012266 salt solution Substances 0.000 description 5
- 239000000243 solution Substances 0.000 description 5
- JEAKTLDJVSMBKC-UHFFFAOYSA-N 2-methylpropane;2-methylprop-1-ene Chemical group CC(C)C.CC(C)=C JEAKTLDJVSMBKC-UHFFFAOYSA-N 0.000 description 4
- RRHGJUQNOFWUDK-UHFFFAOYSA-N Isoprene Chemical compound CC(=C)C=C RRHGJUQNOFWUDK-UHFFFAOYSA-N 0.000 description 4
- 239000011651 chromium Substances 0.000 description 4
- 230000035484 reaction time Effects 0.000 description 4
- DKGAVHZHDRPRBM-UHFFFAOYSA-N Tert-Butanol Chemical compound CC(C)(C)O DKGAVHZHDRPRBM-UHFFFAOYSA-N 0.000 description 3
- 239000010865 sewage Substances 0.000 description 3
- 235000011149 sulphuric acid Nutrition 0.000 description 3
- 239000002351 wastewater Substances 0.000 description 3
- AWBIJARKDOFDAN-UHFFFAOYSA-N 2,5-dimethyl-1,4-dioxane Chemical compound CC1COC(C)CO1 AWBIJARKDOFDAN-UHFFFAOYSA-N 0.000 description 2
- PMZURENOXWZQFD-UHFFFAOYSA-L Sodium Sulfate Chemical compound [Na+].[Na+].[O-]S([O-])(=O)=O PMZURENOXWZQFD-UHFFFAOYSA-L 0.000 description 2
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 2
- JLDSOYXADOWAKB-UHFFFAOYSA-N aluminium nitrate Chemical compound [Al+3].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O JLDSOYXADOWAKB-UHFFFAOYSA-N 0.000 description 2
- 239000006227 byproduct Substances 0.000 description 2
- NKDDWNXOKDWJAK-UHFFFAOYSA-N dimethoxymethane Chemical compound COCOC NKDDWNXOKDWJAK-UHFFFAOYSA-N 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000008098 formaldehyde solution Substances 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 229930195733 hydrocarbon Natural products 0.000 description 2
- 150000002430 hydrocarbons Chemical class 0.000 description 2
- NNPPMTNAJDCUHE-UHFFFAOYSA-N isobutane Chemical compound CC(C)C NNPPMTNAJDCUHE-UHFFFAOYSA-N 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 238000006386 neutralization reaction Methods 0.000 description 2
- 150000002894 organic compounds Chemical class 0.000 description 2
- 238000011084 recovery Methods 0.000 description 2
- 238000013517 stratification Methods 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 229910021653 sulphate ion Inorganic materials 0.000 description 2
- 239000001117 sulphuric acid Substances 0.000 description 2
- 229910002651 NO3 Inorganic materials 0.000 description 1
- 101100386054 Saccharomyces cerevisiae (strain ATCC 204508 / S288c) CYS3 gene Proteins 0.000 description 1
- 230000002378 acidificating effect Effects 0.000 description 1
- 150000001298 alcohols Chemical class 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- 239000012670 alkaline solution Substances 0.000 description 1
- 239000001164 aluminium sulphate Substances 0.000 description 1
- 235000011128 aluminium sulphate Nutrition 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- -1 cyclic alcohols Chemical class 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- BUACSMWVFUNQET-UHFFFAOYSA-H dialuminum;trisulfate;hydrate Chemical compound O.[Al+3].[Al+3].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O BUACSMWVFUNQET-UHFFFAOYSA-H 0.000 description 1
- 150000001993 dienes Chemical class 0.000 description 1
- KTFJRKWUACQCHF-UHFFFAOYSA-N dimethoxymethane;methanol Chemical compound OC.COCOC KTFJRKWUACQCHF-UHFFFAOYSA-N 0.000 description 1
- 150000002009 diols Chemical class 0.000 description 1
- 229920001971 elastomer Polymers 0.000 description 1
- 230000008030 elimination Effects 0.000 description 1
- 238000003379 elimination reaction Methods 0.000 description 1
- 238000000605 extraction Methods 0.000 description 1
- 238000011049 filling Methods 0.000 description 1
- 235000019253 formic acid Nutrition 0.000 description 1
- 150000004674 formic acids Chemical class 0.000 description 1
- 230000003301 hydrolyzing effect Effects 0.000 description 1
- 229910017053 inorganic salt Inorganic materials 0.000 description 1
- BAUYGSIQEAFULO-UHFFFAOYSA-L iron(2+) sulfate (anhydrous) Chemical compound [Fe+2].[O-]S([O-])(=O)=O BAUYGSIQEAFULO-UHFFFAOYSA-L 0.000 description 1
- 229910000359 iron(II) sulfate Inorganic materials 0.000 description 1
- 239000001282 iso-butane Substances 0.000 description 1
- 239000007791 liquid phase Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 239000000178 monomer Substances 0.000 description 1
- 239000010815 organic waste Substances 0.000 description 1
- 229920001195 polyisoprene Polymers 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 239000011541 reaction mixture Substances 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 229910052938 sodium sulfate Inorganic materials 0.000 description 1
- 235000011152 sodium sulphate Nutrition 0.000 description 1
- 101150035983 str1 gene Proteins 0.000 description 1
- 150000003467 sulfuric acid derivatives Chemical class 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07D—HETEROCYCLIC COMPOUNDS
- C07D319/00—Heterocyclic compounds containing six-membered rings having two oxygen atoms as the only ring hetero atoms
- C07D319/04—1,3-Dioxanes; Hydrogenated 1,3-dioxanes
- C07D319/06—1,3-Dioxanes; Hydrogenated 1,3-dioxanes not condensed with other rings
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P20/00—Technologies relating to chemical industry
- Y02P20/50—Improvements relating to the production of bulk chemicals
- Y02P20/582—Recycling of unreacted starting or intermediate materials
Definitions
- the present invention relates to methods of preparing 4,4-dimethyldioxane-1,3.
- Said 4,4-dimethyldioxane-1,3 finds extensive application in the chemical industry in, for instance, the synthesis of isoprene which is a starting monomer for sterospecific polyisoprene rubber.
- the method is carried out as follows; a reaction vessel composed of two series-connected tubular apparatus is inoculated, in countercurrents, with an isobutane fraction and a formaldehyde mix consisting at least 35 percent formaldehyde, and from 1.0 to 2.0 percent sulphuric acid.
- the resulting reaction products viz., dimethyldioxane, diols, trimethyl-carbinol, methylal, unsaturated, and cyclic alcohols, and others, become distributed, depending upon their solubility, between the organic and aqueous phases, whereupon the phases are separated, with the organic phase being washed of the unreacted formaldehyde with a simultaneous neutralization of sulphuric, and formic acids with a weak alkaline solution, after which said phase is fed for rectification.
- the following fractions are distilled off consecutively: hydrocarbons C 4 , methylal-methanol, trimethyl-carbinol, and the end product.
- the aqueous phase is neutralized with an alkali, and subjected to rectification to isolate the high-volatile organic products, such as methylal, trimethylcarbinol, unreacted formaldehyde, dimethyldioxane, etc.
- the water containing the high-boiling organic compounds 3-methylbutanediol-1,3 inclusive, and the sulphates, is discarded into sewerage.
- the isobutylene conversion level is, on an average, from 80 to 82 percent, that of formaldehyde, from 84 to 86 percent.
- the yield of the end product in terms of the converted formaldehyde is from 80 to 82 percent, and that in terms of isobutylene, from 68 to 70 percent.
- the invention consists in that isobutylene is reacted with formaldehyde in an aqueous medium in the presence of a catalyst at a temperature of from 90° to 115° C to form organic and aqueous phases whereupon the organic phase is washed with water and the end product isolated.
- the catalyst used are inorganic salts of mineral acids featuring a pH value of from 2.2 to 4.5 within this aqueous solution.
- the proposed method enables the process to be run with catalyst recycling.
- the recycling of a salt catalyst is accounted for by the fact that the acidity of the aqueous phase and wash water remains invariable, or decreases despite an increase in the salt concentration due to heating. This is not accompanied by resinification of organic products, so that 4,4-dimethyldioxane-1,3 possessing the least hydrolytic stability in acidic media, as well as other products contained in the aqueous phase, exhibit chemical stability when heated.
- the aqueous phase and wash water be evaporated to a level of from 85 to 90 percent so to form a fraction containing the unreacted formaldehyde, and a distillation residue which is essentially an oil bed containing high-boiling organic products, and a salt bed which, after having been separated, is returned, together with the unreacted formaldehyde after having been recovered, to the stage of the reaction of the starting reagents.
- the evaporation process enables the waste water of the process to be completely eliminated.
- a further amount of 4,4-dimethyldioxane-1,3 is also formed during the evaporation process, this being due to the fact that no resinification of the organic products occurs in the presence of the abovesaid salts, which also makes it possible to use 3-methylbutanediol-1,3 for preparing the end product which is formed as reaction by-product with a yield of from 30 to 35 percent with respect to the reacted formaldehyde.
- the herein proposed method enables high-level (up to 85-90 percent) evaporation of the aqueous reaction phase with subsequent separation of the oil bed from the salt solution, with feeding the latter to the stage of interaction of the starting reagents (catalyst recycling).
- Carrying out the process utilizing catalyst recycling enables practically a complete elimination of the organic waste products together with sewage water, and thus attaining a higher selectivity of the process due to the use of 3-methylbutanediol-1,3 which has previously been wasted with sewage water.
- the yield of the end product is increased, as contrasted to the known method, which amounting to from 88 to 90 percent with respect to the reacted formaldehyde.
- the data illustrating the process with recycling the salt catalyst are given in Tables 1 and 2 hereinbelow.
- a starting catalyst is used in the form of an aqueous solution of an inorganic salt whole amount, due to the catalyst recycling according to a closed-circulation circuit, is proportioned by proceeding from an initial filling of the recycle circuit and subsequent slight rep-lenishing there of so to compensate for the catalyst mechanical losses.
- the starting formaldehyde mixture which is an aqueous formaldehyde and salt solution, containing from 35 to 45 percent formaldehyde, and from 2.0 to 2.5 percent anhydrous salt, is prepared by mixing the solutions of both.
- a salt solution resulting from the evaporation of the synthesis aqueous phase is used.
- the reaction is run in the liquid phase in a reaction vessel composed of two series-connected tubular apparatus of the column type, with settling zones provided in the top and bottom portions thereof.
- the formaldehyde mixture and isobutylene or an isobutane-isobutylene fraction, containing from 45 to 50 percent by weight isobutylene, are introduced into the reaction vessel countercurrently.
- the reaction occurs in the tubular portion of the reaction vessel at from 90° to 115° C.
- the reaction provides an organic and an aqueous phase.
- the organic phase containing organic products and C4 hydrocarbons is discharged from the top settling portion of the reaction vessel, washed with water fed in countercurrent, and is then fed for a multistage rectification to isolate the end product, while the wash water, the aqueous phase of the synthesis, and the discharged from the bottom settling zone of the reaction vessel, is fed for processing which consists in isolating the light organic fractions with subsequent high-level evaporation (to 85-90 percent) in order to yield a further amount of the end product due to the conversion of 3-methylbutanediol-1,3, and stratification of the reaction mass into an oil bed, and a salt bed (a saturated salt solution) which is returned, after being separated from the oil bed, to the stage of interaction of the starting reagents (catalyst recycling).
- the evaporation fraction is fed for formaldehyde recovery, whereupon the recycle formaldehyde is fed to the stage of preparing
- the salts proposed as catalysts can be useful in interreactions of an aqueous formaldehyde with a concentrated isobutylene and an isobutane-isobutylene fraction, containing from 45 to 50 weight percent isobutylene.
- the formaldehyde conversion level attained is quite suitable for industrial conditions (refer to Table 3 below).
- a stainless-steel reaction vessel equipped with a stirrer, a thermocouple, and heating-and-cooling jacket is inoculated with 776.5 g of a formaldehyde mix in the form of a 38.2 percent aqueous formaldehyde solution, containing 3 weight percent Cr 2 (SO 4 ) 3 .6H 2 O, and 930 g of preliminarily condensed isobutylene with a 99.8-percent concentration.
- the reaction mixture is heated to 90° C and stirred at that temperature for 60 minutes. After having been cooled the reaction mass is separated into organic and aqueous phases.
- the end product is rectification-isolated, whereas the wash water is mixed with the aqueous phase, and vacuum-evaporated to a 85-percent level.
- the resultant distillation residue is stratified, whereupon the salt bed is separated from the oil bed and fed as a catalyst to the stage of interaction of the starting reagents.
- the evaporation fraction is fed to formaldehyde recovery which is then also returned for the stage of interaction of the starting reagents.
- the yield of end product equals 89.1 percent with respect to the reacted formaldehyde, with the formaldehyde conversion percentage being 96.3.
- the yield of with the end product is 88.25 percent, the formaldehyde conversion level being 90.55 percent.
- a preliminarily cooled stainless-steel flask is inoculated with 37 g formalin having a 36.5-percent concentration, 0.708 g K 2 Cr 2 /SO 4 / 4 .24H 2 O, and 17.5 g of a condensed liquid isobutylene having a 99.8-percent concentration. Then the hermetically sealed flask is placed, for the reaction time, into a temperature-controlled cabinet provided with a shaker heated to 105° C, whereupon the shaker is put into operation. The reaction time is 2 hours from the starting of the shaker. Upon termination of the reaction the flask is quickly cooled and the resultant organic phase, after stratification, is separated from the aqueous phase, whereupon the end product is isolated from the reaction phases.
- the yield of the end product is 83.9 percent, with the formaldehyde conversion level being 88.65 percent.
- a preliminarily cooled stainless-steel flask is inoculated 37 g formalin having a 36.25-percent concentration, 0.602 g FeSO 4 /NH 4 / 2 SO 4 .6H 2 O, and 17.5 g of a condensed liquid isobutylene having a 99.8-percent concentration.
- the experiment is run similarly to that as described in Example 1.
- the yield of the end product is 85.7 percent, with the formaldehyde conversion level being 81.05 percent.
- a stainless-steel reaction vessel provided with a stirrer, a thermocouple and a heating-and-cooling jacket is inoculated with 258.8 g of a formaldehyde mix which mix is essentially an aqueous formaldehyde and potassium bifluoride solution containing 40 percent formaldehyde, and 3 percent KHF 2 , and 310 g of a preliminarily condensed isobutylene having a 99.8-percent concentration.
- the experiment proceeds at 95° C for 2 hours as described in Example 1.
- the yield of the end product is 80 percent, with the formaldehyde conversion level being 91.2 percent.
- a stainless-steel reaction vessel provided with a stirrer, a thermocouple and a heating-and-cooling jacket is inoculated with 517 g of a formaldehyde mix, viz., a 39-percent aqueous formalin solution, containing 3 weight percent Al 3 (NO 3 ) 3 .9H 2 O, and 620 g of a preliminarily condensed isobutylene having 99.8-percent concentration.
- the experiment is run at 95° C for two hours as described in Example 1.
- the yield of 4,4-dimethyldioxane-1,3 is 65 percent, that of unsaturated alcohols, 15 percent, isoprene, 10 percent.
- the formaldehyde conversion level is 95 percent.
- a stainless-steel reaction vessel provided with a stirrer, a thermocouple, and a heating-and-cooling jacket is inoculated with 776.5 g of a formaldehyde mix, viz., a 40-percent aqueous formalin solution, containing 3 weight percent CrCl 3 .10H 2 O, and 930 g of a preliminarily condensed isobutylene having a 99.8-percent concentration.
- the experiment occurs at 95° C for 2 hours as described in Example 1.
- the 4,4-dimethyldioxane-1,3 yield is 78 percent, with the formaldehyde conversion percentage being 87.3.
Abstract
The method of preparing 4,4-dimethyldioxane-1,3 consists in the interaction of isobutylene and formaldehyde in an aqueous medium at from 90 DEG to 115 DEG C in the presence of a catalyst, the capacity of which such inorganic salts of mineral acids may be used with the pH value of the aqueous solutions whereof being within 2.2 to 4.5, resulting in the formation of an organic and an aqueous phase containing the end product, followed by the separation of said phases, washing the organic phase with water, and isolation of the end product.
Description
This is a continuation of application Ser. No. 484,788 filed July 1, 1974, now abandoned.
The present invention relates to methods of preparing 4,4-dimethyldioxane-1,3.
Said 4,4-dimethyldioxane-1,3 finds extensive application in the chemical industry in, for instance, the synthesis of isoprene which is a starting monomer for sterospecific polyisoprene rubber.
An industrial method of preparing 4,4-dimethyldioxane-1,3 is known in the art (of. a monograph entitled "A new method of synthesis of divinyl-series dienes" by M.I. Farberov, Moscow, 1952 /in Russian/). The method consists in interaction of isobutylene and formaldehyde in an aqueous medium at a temperature of from 80° to 100° C and a pressure of from 16 to 20 atm. gauge in the presence of sulphuric acid as a catalyst. The method is carried out as follows; a reaction vessel composed of two series-connected tubular apparatus is inoculated, in countercurrents, with an isobutane fraction and a formaldehyde mix consisting at least 35 percent formaldehyde, and from 1.0 to 2.0 percent sulphuric acid. The resulting reaction products, viz., dimethyldioxane, diols, trimethyl-carbinol, methylal, unsaturated, and cyclic alcohols, and others, become distributed, depending upon their solubility, between the organic and aqueous phases, whereupon the phases are separated, with the organic phase being washed of the unreacted formaldehyde with a simultaneous neutralization of sulphuric, and formic acids with a weak alkaline solution, after which said phase is fed for rectification. During rectification, the following fractions are distilled off consecutively: hydrocarbons C4, methylal-methanol, trimethyl-carbinol, and the end product. The aqueous phase is neutralized with an alkali, and subjected to rectification to isolate the high-volatile organic products, such as methylal, trimethylcarbinol, unreacted formaldehyde, dimethyldioxane, etc. The water containing the high-boiling organic compounds 3-methylbutanediol-1,3 inclusive, and the sulphates, is discarded into sewerage. The isobutylene conversion level is, on an average, from 80 to 82 percent, that of formaldehyde, from 84 to 86 percent. The yield of the end product in terms of the converted formaldehyde is from 80 to 82 percent, and that in terms of isobutylene, from 68 to 70 percent.
The disadvantages inherent in said known method reside in the presence of large amounts of by-products that are liable to form during the reaction, thus necessitating the neutralization of the organic and aqueous phases, disposal of large quantities of sewage water containing a great proportion of high-boiling organic products, and sodium sulphate; a problem also arises concerned with ridding the water phase of organic compounds.
It is an essential object of the present invention to develop a method of preparing 4,4-dimethyldioxane-1,3 such that would make it possible to render the process more selective.
It is another object of the present invention to increase the yield of the end product due to the extraction of 3-methylbutanediol-1,3, as well as to completely eliminate process waste water.
According to said and other objects, the invention consists in that isobutylene is reacted with formaldehyde in an aqueous medium in the presence of a catalyst at a temperature of from 90° to 115° C to form organic and aqueous phases whereupon the organic phase is washed with water and the end product isolated. According to the invention, the catalyst used are inorganic salts of mineral acids featuring a pH value of from 2.2 to 4.5 within this aqueous solution.
The process carried out in the presence of said salts under the above-specified conditions results in a reduced total amount of high-boiling products, i.e., in a higher selectivity for the process.
The proposed method enables the process to be run with catalyst recycling.
In order to effect catalyst recycling, it is expedient to use, as the latter said salts, the acidity of the aqueous solutions which is either invariable or reduced with an increase in the salt concentration.
The recycling of a salt catalyst is accounted for by the fact that the acidity of the aqueous phase and wash water remains invariable, or decreases despite an increase in the salt concentration due to heating. This is not accompanied by resinification of organic products, so that 4,4-dimethyldioxane-1,3 possessing the least hydrolytic stability in acidic media, as well as other products contained in the aqueous phase, exhibit chemical stability when heated.
It is expedient, for the purpose of returning the salt catalyst into the reaction and ruling out the waste water from the process, that the aqueous phase and wash water be evaporated to a level of from 85 to 90 percent so to form a fraction containing the unreacted formaldehyde, and a distillation residue which is essentially an oil bed containing high-boiling organic products, and a salt bed which, after having been separated, is returned, together with the unreacted formaldehyde after having been recovered, to the stage of the reaction of the starting reagents. Thus, the evaporation process enables the waste water of the process to be completely eliminated.
A further amount of 4,4-dimethyldioxane-1,3 is also formed during the evaporation process, this being due to the fact that no resinification of the organic products occurs in the presence of the abovesaid salts, which also makes it possible to use 3-methylbutanediol-1,3 for preparing the end product which is formed as reaction by-product with a yield of from 30 to 35 percent with respect to the reacted formaldehyde. When evaporating the synthesis aqueous reaction phase, and the wash water after washing the organic phase in the presence of said salts, 3-methylbutanediol-1,3 is completely converted into the end product due to its being reacted with the unreacted formaldehyde contained in the aqueous phase, according to the following reaction diagram: ##STR1##
The procedure ensures from all discussed above that 4,4-dimethyldioxane-1,3 can be prepared from 3-methylbutanediol-1,3 in the presence of said salt catalysts.
Thus, as compared to the known method, the herein proposed method enables high-level (up to 85-90 percent) evaporation of the aqueous reaction phase with subsequent separation of the oil bed from the salt solution, with feeding the latter to the stage of interaction of the starting reagents (catalyst recycling). Carrying out the process utilizing catalyst recycling enables practically a complete elimination of the organic waste products together with sewage water, and thus attaining a higher selectivity of the process due to the use of 3-methylbutanediol-1,3 which has previously been wasted with sewage water. The yield of the end product is increased, as contrasted to the known method, which amounting to from 88 to 90 percent with respect to the reacted formaldehyde. The data illustrating the process with recycling the salt catalyst are given in Tables 1 and 2 hereinbelow.
The proposed method is carried into effect preferably as follows:
A starting catalyst is used in the form of an aqueous solution of an inorganic salt whole amount, due to the catalyst recycling according to a closed-circulation circuit, is proportioned by proceeding from an initial filling of the recycle circuit and subsequent slight rep-lenishing there of so to compensate for the catalyst mechanical losses.
The starting formaldehyde mixture, which is an aqueous formaldehyde and salt solution, containing from 35 to 45 percent formaldehyde, and from 2.0 to 2.5 percent anhydrous salt, is prepared by mixing the solutions of both. In catalyst recycling, for the preparation of the formaldehyde mixture, a salt solution resulting from the evaporation of the synthesis aqueous phase is used.
Table 1
__________________________________________________________________________
Data on salt catalyst recycling, involving high-level
evaporation of the aqueous reaction phase /catalyst-
Cr.sub.2 (SO.sub.4).sub.3 /. Reaction temperature - 95°, reaction
time 80 min., molar ratio of iC.sub.4 H.sub.8 to CH.sub.2 O - 1.15,
starting amount of catalyst is 2.5%
__________________________________________________________________________
CH.sub.2 O
con- CH.sub.2 O con-
version
centra-
Yield of
Percentage of
Amount of recycled
Re-
per- tion in
4,4-dimethyl-
high-boiling
salt solution, %
cycle
cent-
starting
dioxane-
products in
of aqueous phase
No.
age mixture,%
1,3,% organic phase
and wash water
__________________________________________________________________________
1 90.1 42.0 87.8 5.82 5.86
2 88.7 41.9 88.3 5.29 5.45
3 88.1 40.7 88.2 5.23 5.26
4 87.3 41.2 87.9 4.86 5.85
5 87.8 41.7 89.6 4.36 4.94
6 86.3 40.9 88.6 4.25 4.67
7 87.3 41.2 88.9 4.10 4.83
8 86.4 39.4 88.2 4.02 4.75
9 86.2 40.2 88.1 4.11 5.85
10 86.9 40.8 88.9 4.10 5.71
__________________________________________________________________________
Table 2
__________________________________________________________________________
Data on variation of 3-methylbutanediol-1,3 content
as a result of heating the aqueous phase of 4,4-dimethyl-
dioxane-1,3 synthesis in the presence of chromium
sulphate (reaction time - 2 hours, temperature 100° C)
__________________________________________________________________________
3-methyl-
butanediol-
4,4-dimethyl- Dioxane alco-
Descrip-
1,3 dioxane-1,3
CH.sub.2 O
hols H.sub.2 O
tion % g % g % g % g % g
__________________________________________________________________________
Start-
ing test
7.5 10.6
none
none
23.7
33.4
29.5
41.6
39.3
55.4
Postreac-
tion ana-
lysis
none
none
7.8 11.0
19.6
27.7
29.5
41.6
43.1
60.7
__________________________________________________________________________
The reaction is run in the liquid phase in a reaction vessel composed of two series-connected tubular apparatus of the column type, with settling zones provided in the top and bottom portions thereof. The formaldehyde mixture and isobutylene or an isobutane-isobutylene fraction, containing from 45 to 50 percent by weight isobutylene, are introduced into the reaction vessel countercurrently. The reaction occurs in the tubular portion of the reaction vessel at from 90° to 115° C.
The reaction provides an organic and an aqueous phase. The organic phase, containing organic products and C4 hydrocarbons is discharged from the top settling portion of the reaction vessel, washed with water fed in countercurrent, and is then fed for a multistage rectification to isolate the end product, while the wash water, the aqueous phase of the synthesis, and the discharged from the bottom settling zone of the reaction vessel, is fed for processing which consists in isolating the light organic fractions with subsequent high-level evaporation (to 85-90 percent) in order to yield a further amount of the end product due to the conversion of 3-methylbutanediol-1,3, and stratification of the reaction mass into an oil bed, and a salt bed (a saturated salt solution) which is returned, after being separated from the oil bed, to the stage of interaction of the starting reagents (catalyst recycling). The evaporation fraction is fed for formaldehyde recovery, whereupon the recycle formaldehyde is fed to the stage of preparing the formaldehyde mix.
The salts proposed as catalysts can be useful in interreactions of an aqueous formaldehyde with a concentrated isobutylene and an isobutane-isobutylene fraction, containing from 45 to 50 weight percent isobutylene. The formaldehyde conversion level attained is quite suitable for industrial conditions (refer to Table 3 below).
Table 3
__________________________________________________________________________
Formaldehyde conversion percentage and selectivity
of 4,4-dimethyldioxane-1,3 synthesis in the presence
of aluminium sulphate versus reaction temperature
__________________________________________________________________________
Conditions of synthesis Conversion
Yield percent-
tempera-
reaction
isobutyelene
percentage
age of 4,4-
ture, time, concentra-
of dimethyl-
Nos ° C
hours tion,% CH.sub.2 O
dioxane-1,3
__________________________________________________________________________
1 80 2 99.2 37.3 87.2
2 100 2 99.2 79.7 85.7
3 110 2 99.2 85.3 85.4
4 120 2 99.2 91.0 83.8
5 110 1 46.0 60.0 81.6
6 120 1 47.0 93.0 83.8
7 130 0.5 47.0 88.0 85.4
__________________________________________________________________________
In order to romote better understanding of the present invention, given below are the following examples of practical embodiment thereof.
A stainless-steel reaction vessel equipped with a stirrer, a thermocouple, and heating-and-cooling jacket is inoculated with 776.5 g of a formaldehyde mix in the form of a 38.2 percent aqueous formaldehyde solution, containing 3 weight percent Cr2 (SO4)3.6H2 O, and 930 g of preliminarily condensed isobutylene with a 99.8-percent concentration. The reaction mixture is heated to 90° C and stirred at that temperature for 60 minutes. After having been cooled the reaction mass is separated into organic and aqueous phases. From the organic phase, after its having been washed with water, the end product is rectification-isolated, whereas the wash water is mixed with the aqueous phase, and vacuum-evaporated to a 85-percent level. The resultant distillation residue is stratified, whereupon the salt bed is separated from the oil bed and fed as a catalyst to the stage of interaction of the starting reagents. The evaporation fraction is fed to formaldehyde recovery which is then also returned for the stage of interaction of the starting reagents.
The yield of end product equals 89.1 percent with respect to the reacted formaldehyde, with the formaldehyde conversion percentage being 96.3.
770 g of formaldehyde mix are introduced into a stainless-steel reaction vessel provided with a stirrer, a thermocouple and a heating-and-cooling jacket mix being in the form of an aqueous formaldehyde, and chromium sulphate solution, containing 40 percent formaldehyde and 3 percent Cr2 (SO4)3.6H2 O, and 1300 g of a preliminarily condensed isobutane-isobutylene fraction containing 47.4 weight percent isobutylene. The experiment is run at 95° C for 80 minutes similarly to that as described in Example 1.
The yield of with the end product is 88.25 percent, the formaldehyde conversion level being 90.55 percent.
A preliminarily cooled stainless-steel flask is inoculated with 37 g formalin having a 36.5-percent concentration, 0.708 g K2 Cr2 /SO4 /4.24H2 O, and 17.5 g of a condensed liquid isobutylene having a 99.8-percent concentration. Then the hermetically sealed flask is placed, for the reaction time, into a temperature-controlled cabinet provided with a shaker heated to 105° C, whereupon the shaker is put into operation. The reaction time is 2 hours from the starting of the shaker. Upon termination of the reaction the flask is quickly cooled and the resultant organic phase, after stratification, is separated from the aqueous phase, whereupon the end product is isolated from the reaction phases.
The yield of the end product is 83.9 percent, with the formaldehyde conversion level being 88.65 percent.
A preliminarily cooled stainless-steel flask is inoculated 37 g formalin having a 36.25-percent concentration, 0.602 g FeSO4 /NH4 /2 SO4.6H2 O, and 17.5 g of a condensed liquid isobutylene having a 99.8-percent concentration. The experiment is run similarly to that as described in Example 1.
The yield of the end product is 85.7 percent, with the formaldehyde conversion level being 81.05 percent.
A stainless-steel reaction vessel provided with a stirrer, a thermocouple and a heating-and-cooling jacket is inoculated with 258.8 g of a formaldehyde mix which mix is essentially an aqueous formaldehyde and potassium bifluoride solution containing 40 percent formaldehyde, and 3 percent KHF2, and 310 g of a preliminarily condensed isobutylene having a 99.8-percent concentration. The experiment proceeds at 95° C for 2 hours as described in Example 1.
The yield of the end product is 80 percent, with the formaldehyde conversion level being 91.2 percent.
A stainless-steel reaction vessel provided with a stirrer, a thermocouple and a heating-and-cooling jacket is inoculated with 517 g of a formaldehyde mix, viz., a 39-percent aqueous formalin solution, containing 3 weight percent Al3 (NO3)3.9H2 O, and 620 g of a preliminarily condensed isobutylene having 99.8-percent concentration. The experiment is run at 95° C for two hours as described in Example 1.
The yield of 4,4-dimethyldioxane-1,3 is 65 percent, that of unsaturated alcohols, 15 percent, isoprene, 10 percent. The formaldehyde conversion level is 95 percent.
A stainless-steel reaction vessel provided with a stirrer, a thermocouple, and a heating-and-cooling jacket is inoculated with 776.5 g of a formaldehyde mix, viz., a 40-percent aqueous formalin solution, containing 3 weight percent CrCl3.10H2 O, and 930 g of a preliminarily condensed isobutylene having a 99.8-percent concentration. The experiment occurs at 95° C for 2 hours as described in Example 1.
The 4,4-dimethyldioxane-1,3 yield is 78 percent, with the formaldehyde conversion percentage being 87.3.
Claims (3)
1. A method of preparing 4,4-dimethyldioxane-1,3 comprising reacting isobutylene with formaldehyde in an aqueous medium at 90°-115° C in the presence of a catalyst comprising inorganic salts of mineral acids, whose aqueous solutions have a pH value of from 2.2 to 4.5 and whose acidity of said aqueous solutions does not increase with an increase in the salt concentration said inorganic salts being selected from the group consisting of chromium sulfate, chromic potassium sulfate, ferriamonium sulfate, potassium bifluoride, aluminum nitrate, and chromium trichloride, to form organic and aqueous phases containing the end product; separating said phases; washing the organic phase with water; and isolating the end product.
2. The method as claimed in claim 1, wherein the aqueous phase and wash water are evaporated to a level of from 85 to 90 percent to form a fraction containing the unreacted formaldehyde, and a distillation residue, which is an oil bed, and a salt bed, with the latter, after having been separated, being returned to the stage of reaction of the starting reagents.
3. A method as claimed in claim 2, wherein the unreacted formaldehyde is recovered from the fraction and returned to the stage of reacting of the starting reagents.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB2913274A GB1418608A (en) | 1974-07-01 | 1974-07-01 | Method of preparing 4,4-dimethyl-1,3-dioxan |
| US05/569,388 US4017518A (en) | 1974-07-01 | 1975-04-18 | Method of preparing 4,4-dimethyldioxane-1,3 |
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US48478874A | 1974-07-01 | 1974-07-01 | |
| GB2913274A GB1418608A (en) | 1974-07-01 | 1974-07-01 | Method of preparing 4,4-dimethyl-1,3-dioxan |
| US05/569,388 US4017518A (en) | 1974-07-01 | 1975-04-18 | Method of preparing 4,4-dimethyldioxane-1,3 |
Related Parent Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US48478874A Continuation | 1974-07-01 | 1974-07-01 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| US4017518A true US4017518A (en) | 1977-04-12 |
Family
ID=27258791
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US05/569,388 Expired - Lifetime US4017518A (en) | 1974-07-01 | 1975-04-18 | Method of preparing 4,4-dimethyldioxane-1,3 |
Country Status (2)
| Country | Link |
|---|---|
| US (1) | US4017518A (en) |
| GB (1) | GB1418608A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1981000408A1 (en) * | 1979-07-31 | 1981-02-19 | S Ogorodnikov | Method of obtaining alkyl dioxanes-1,3 |
| US4448980A (en) * | 1983-09-22 | 1984-05-15 | E. I. Du Pont De Nemours And Company | Preparation of trialkylsilyl ethers |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS57500103A (en) * | 1980-02-13 | 1982-01-21 |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2490276A (en) * | 1946-04-12 | 1949-12-06 | Standard Oil Dev Co | Preparation of triptane structure compounds |
| CA475546A (en) * | 1951-07-24 | Standard Oil Development Company | Metadioxanes produced from aldehydes and olefinic compounds | |
| US3414588A (en) * | 1964-01-29 | 1968-12-03 | Mobil Oil Corp | Condensation of aldehydes with unsaturated compounds |
-
1974
- 1974-07-01 GB GB2913274A patent/GB1418608A/en not_active Expired
-
1975
- 1975-04-18 US US05/569,388 patent/US4017518A/en not_active Expired - Lifetime
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA475546A (en) * | 1951-07-24 | Standard Oil Development Company | Metadioxanes produced from aldehydes and olefinic compounds | |
| US2490276A (en) * | 1946-04-12 | 1949-12-06 | Standard Oil Dev Co | Preparation of triptane structure compounds |
| US3414588A (en) * | 1964-01-29 | 1968-12-03 | Mobil Oil Corp | Condensation of aldehydes with unsaturated compounds |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1981000408A1 (en) * | 1979-07-31 | 1981-02-19 | S Ogorodnikov | Method of obtaining alkyl dioxanes-1,3 |
| US4448980A (en) * | 1983-09-22 | 1984-05-15 | E. I. Du Pont De Nemours And Company | Preparation of trialkylsilyl ethers |
Also Published As
| Publication number | Publication date |
|---|---|
| GB1418608A (en) | 1975-12-24 |
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